How to identify which Wiper Motor (2 speed or 3 speed) Should be on 75 Duster

The 2 speed motor has wires that attach with plug-ins at the motor, whereas the 3/variable speed motor is wired directly into the motor inside the case, so there may be telltale evidence there. Swapping from 2-3 speed and visa versa is not uncomplicated - a lot of work to have a less desirable system, so why would someone do that?